Oral Presentation ESA-SRB-AOTA 2019

Risk of polycythaemia with different formulations of testosterone therapy in transgender men (#53)

Brendan J Nolan 1 2 , Shalem Y Leemaqz 3 , Olivia Ooi 1 , Pauline Cundill 4 , Nicholas Silberstein 4 , Peter Locke 4 , Mathis Grossmann 2 5 , Jeffrey D Zajac 1 2 , Ada S Cheung 1 2
  1. Trans Medical Research Group, Department of Medicine (Austin Health), University of Melbourne, HEIDELBERG, VIC, Australia
  2. Department of Endocrinology, Austin Health, Heidelburg, VIC, Australia
  3. Robinson Research Institute, Adelaide Medical School, University of Adelaide, ADELAIDE, SA, Australia
  4. Equinox Gender Diverse Clinic, Thorne Harbour Health, FITZROY, VIC, Australia
  5. Department of Medicine (Austin Health), HEIDELBERG, VIC, Australia

Background: Masculinising hormone therapy with testosterone is used to align an individual’s physical characteristics with their gender identity. Testosterone therapy can be administered via intramuscular or transdermal routes and polycythaemia is the most common adverse event. We aimed to compare the risk of polycythaemia with different formulations of testosterone therapy in transgender men.

 

Methods: A retrospective cross-sectional analysis was performed of 180 transgender individuals attending gender clinics in Melbourne who were on established testosterone therapy for > 6 months and had haematocrit available. Groups included those receiving (1) intramuscular testosterone undecanoate (n=125), (2) intramuscular testosterone enanthate (n=31), or (3) transdermal testosterone (n=24). Outcomes were haematocrit level and polycythaemia (defined as haematocrit >0.5). Mean (SD) or median (IQR) are reported as appropriate. Kruskal-wallis test was used to compare haematocrit levels between testosterone therapy groups, and Fisher’s exact test was performed for polycythaemia with Bonferroni adjusted pairwise comparisons.

 

Results: 180 individuals (mean age 28.4(8.8) years)) had data available for analysis. Median duration of testosterone therapy was 37.7 (24.2) months. 27% were smokers. There was no difference between groups in serum total testosterone levels achieved (mean 12.6 nmol/L (10.8) for testosterone undecanoate, 12.1 nmol/L (10.4) for testosterone enanthate and 10 nmol/L (10.8 nmol/L) for transdermal testosterone, overall p=0.347). Box plots of haematocrit levels by group are shown in Figure 1. There was a higher proportion of patients with polycythemia in those who were on intramuscular testosterone enanthate (23.3%) than on transdermal testosterone (0%), p=0.043. There was no statistically significant difference in polycythaemia between intramuscular testosterone undecanoate (15%) and transdermal (0%), p=0.066.

 

Conclusions: Intramuscular testosterone is associated with a higher risk of polycythaemia than transdermal testosterone in transgender men. This highlights the importance of regular monitoring of haematocrit in transgender men treated with testosterone and findings may inform treatment choices.5cf50d3fa88d5-T+HCT.png